Using salt-tolerant bacteria to protect plants from salt stress is a promising microbiological treatment strategy for saline–alkali soil improvement. Here, we conducted research on the growthpromoting effect of
Brevibacterium frigoritolerans
on wheat under salt stress, which has rarely been addressed before. The synergistic effect of
B. frigoritolerans
combined with representative salttolerant bacteria
Bacillus velezensis
and
Bacillus thuringiensis
to promote the development of wheat under salt stress was also further studied. Our approach involved two steps: investigation of the plant growth-promoting traits of each strain at six salt stress levels (0, 2, 4, 6, 8, and 10%); examination of the effects of the strains (single or in combination) inoculated on wheat in different salt stress conditions (0, 50, 100, 200, 300, and 400 mM). The experiment of plant growth-promoting traits indicated that among three strains,
B. frigoritolerans
had the most potential for promoting wheat parameters. In single-strain inoculation,
B. frigoritolerans
showed the best performance of plant growth promotion. Moreover, a pot experiment proved that the plant growth-promoting potential of co-inoculation with three strains on wheat is better than single-strain inoculation under salt stress condition. Up to now, this is the first report suggesting that
B. frigoritolerans
has the potential to promote wheat growth under salt stress, especially combined with
B. velezensis
and
B. thuringiensis
.